The present invention relates to orthopedic surgical instrumentation, and more particularly relates to an improved fixator for use in the treatment of bone fractures such as distal radius fractures. Even more particularly, the present invention relates to an improved external fixator for the treatment of distal radius and other like bone fractures that will assist the surgeon in restoring anatomy of a fracture following an injury by allowing the surgeon to quickly manipulate the fixator to apply force to the ligaments in several directions so that the ligaments will reposition the bone fragments in their correct anatomical position and wherein the fixator includes a unique clamp arrangement that fully articulates, yet can be rigidly affixed in a selected configuration by tightening a single connector.
One of the most common fractures that is treated in emergency rooms is a distal radius fracture sometimes classified as a Colles fracture. One of the popular methods of treating distal radius fractures is to apply an external fixator for the purpose of reducing the fracture by ligamentotaxis, which is a method of distracting the wrist to allow the ligaments to push the bone fragments back in place.
Simple distraction of the wrist is sufficient to restore the original length of the radius, but may not adequately restore other anatomical features such as the tilt angle of the radial head commonly referred to as the radial tilt and the volar tilt.
An example of a technique of multiplanar ligamentotaxis is described by Dr. John Agee in an article published in Orthopedic Clinics of North America, Volume 24, No. 2, April 1993 and entitled xe2x80x9cExternal Fixation: Technical Advances Based Upon Multiplanar Ligamentotaxisxe2x80x9d. John Agee is the named patentee of three (3) United States patents, namely, U.S. Pat. Nos. 4,548,199; 4,611,586; and 4,922,856. The fixator developed by Dr. Agee provides a method of achieving multiplanar ligamentotaxis through gradual turning of worm screws.
Several fixation systems have been patented that relate to the holding of bone segments. An example is U.S. Pat. No. 4,483,334, issued to William Murray and entitled xe2x80x9cExternal Fixation Devicexe2x80x9d. The ""334 patent discloses a device for holding bone segments in known relation to each other. The apparatus includes a pair of bone clamp assemblies each secured to bone pins extending from the bone segments. A bridge extends between the pin clamp assemblies and a specialized high friction universal assembly connects the bridge to each of the pin clamp assemblies.
U.S. Pat. No. 5,207,676, issued to Jose Canadell et al., relates to an external fixator with controllable damping. This external fixator disclosed in the ""676 patent is for the correction and reduction of bone fragments. The apparatus comprises a bar fastened to a biocompression system on which the bar and system are disposed upon supports for fastening pins inserted into bones.
A spinal fixator reduction frame is the subject of U.S. Pat. No. 5,219,349. A reduction frame disclosed in the ""349 patent is secured to shaft handles extending from the pedicle screws of a Vermont Spinal Fixator type implant. Shaft clamps secure two T-handles of the reduction frame to the shaft handles. A lower-rod assembly joins the two opposite T-frames by means of lower-rod clamps. The shaft clamps are provided with four degrees of freedom. The joint between the lower-rod assembly and T-handle is provided with five degrees of freedom. The lower-rod assembly and the T-handle are provided with power screw threads to allow for precise translational control. The shaft clamps and lower-rod clamps are provided with taper fit joints to allow for infinite rotational adjustment and fixture. An upper-rod assembly is also provided on the T-handles to produce rotation of the T-handles by providing means for changing the distance between the upper ends of the T-handles. Finger grips are provided on the upper-rod assembly to allow the surgeon to easily use one hand to either apply or monitor the force acting along the upper-rod.
The Hardy U.S. Pat. No. 5,429,637, discloses an external modular fixator for immobilization of a fracture. The apparatus includes elements functioning as clamps and receiving anchor pins to be fixed in a predetermined angular position on either side of a fracture. A mobilization relay body is configured to be attached to the fracture. The mobilization body has a device for locking which is used to lock the clamps. A fixator and the mobilization relay bodies are lockable in various chosen arrangements. The device is shown affixed to a patient""s lower arm and wrist area.
The Pennig U.S. Pat. No. 5,443,465 refers to an osteosynthesis aid which is used in particular for the fixation of a pelvis and includes a central body which is formed of at least two arm or link members, each of which has an elongated slot through which a lock bolt is passed to provide a releasable clamped joint and each of which also has releasably secured ball-joint connection to an end-connecting clamp for bone-pin or bone-screw anchorage to an afflicted bone.
A Russian Patent SU 1491-492-A1 discloses a femur neck fracture osteosynthesis device that has a support in the form of plates with inclined slots for pins. The plates have apertures for pin locks. The pin locks are designed in the form of threaded rods with nuts and washers. The plates are in parallel plane with an offset greater than the sum of the thickness of the plates and the pin diameter. The plates are interconnected by connecting pieces. Pins are passed after passing through the aiming pin and are locked by the pin locks. This device has an advantage of simplifying the design by allowing crossing-over angle in the planes parallel with the femur axis.
A patent that relates generally to orienting and securing a rod in a spatially adjusted position is the subject of the Jaquet U.S. Pat. No. 3,961,854, entitled xe2x80x9cApparatus For Orienting And Maintaining A Rod In Any Directionxe2x80x9d. The Jaquet patent discusses maintaining an object which one desires to place in diverse orientations as for example, a table lamp, a reflector, and also to employ the same in surgical uses.
The present invention provides an improved bone fixator that enables the orthopedic surgeon to restore the patient""s anatomy at a fracture following an injury. The present invention enables a surgeon to quickly manipulate the fixator and an articulating clamp (or clamps) to apply force to the ligaments in several directions so that the ligaments will reposition the bone fragments in their correct anatomical position and wherein a single fastener is tightened to rigidify the clamp and bone parts connected thereto.
Multiple pin clamps are placed along a rod to secure the rod to the bone. The pin clamps allow rotation around the bar as well as rotation around the clamp to allow the pins to be placed at a wide variety of angles and in multiple planes. A double pin clamp can be used to secure pins into selected bone parts such as the metacarpals of the hand. The multiple pin clamp also allows rotation about two axes. It can be rigidified in a selected position with a single fastener.
In the preferred embodiment, the pins are secured to the clamp by set screws. However, other clamping methods may be used (for example, clam shell clamps). The restoration of anatomical length is achieved by sliding the pin clamps along the rod to distract the ligaments.
For a wrist fracture, restoration of the volar tilt is achieved by loosening the set screws on the metacarpal pin clamp and rotating the rod to allow a vertical translation of the metacarpal pin clamp. Radial tilt can be restored by translating the metacarpal pins through the clamp to shift the wrist sideways. In extreme cases, the rotation can be adjusted by tightening the metacarpal pin clamp to the rod and rotating the rod.
The present invention provides an improved fixator apparatus for distal radius fractures that includes an elongated support rod having proximal and distal rod sections joined by a transverse rod section that offsets the proximal and distal rod sections. A pair of bends integrally joins the proximal and distal rod sections to the transverse rod section. Radius fixation pins are provided for engaging a patient""s radius bone tissue.
Radius support clamps are rotatably supported upon the proximal rod section for externally supporting the patient""s distal radius, the support clamps including openings that support the radius fixation pins. The support clamps allow rotation relative to the rod and relative to the radius fixation pins. Metacarpal fixation pins are provided for engaging the patient""s metacarpal bone tissue.
Hand support clamps are rotatably supported upon the distal rod section for externally supporting the patient""s hand. The hand support clamps include openings for holding the metacarpal fixation pins, the hand support clamps allowing rotation relative to the rod and relative to the metacarpal fixation pins. The proximal and distal rod sections are preferably generally parallel.
The proximal rod section has a central longitudinal axis and the radius support clamp and rod are so configured that the distal rod section is rotatable during use about the central longitudinal axis of the proximal rod section.
The metacarpal support clamp is slidable along the distal rod section during use for distracting the ligaments of the patient""s wrist.
The rod and support clamps are so configured that volar tilt is achieved by rotating the distal rod section relative to the proximal rod section when the support clamps are rotated with respect to the rod.